A general analysis is made of the propagation of magnetostatic bulk waves in an arbitrarily magnetized YIG film separated from a perfect conductor by a dielectric layer. Using the transformed permeability tensor, the magnetostatic equations are solved subject to appropriate boundary conditions in order to obtain the dispersion relation and an expression for the group delay time. Numerical calculations indicate that, in general, the propagation characteristics are non‐reciprocal and the delay curves contain forward as well as backward wave branches. Whereas the forward waves are non‐dispersive over a small bandwidth, no such region of non‐dispersive delay occurs for backward waves. The effect of small deviations from the states of normal magnetization and in‐plane magnetization are also investigated numerically.